Enhanced IPM of Rose Stem Girdler, an Emerging Pest of Pacific Northwest Caneberries

Rose stem girdler (RSG) is an invasive beetle pest of caneberry crops that is becoming increasingly problematic for Pacific Northwest (PNW) growers. It has progressively become naturalized throughout the northern Willamette Valley northward to the south Puget Sound region throughout the 2000s-present due to abundant wild bramble hosts. Grower reports of damage to crops has been variable, but with incidental claims of up to ~70% crop loss in a given year due to cane girdling by the beetle’s larvae. Control has been difficult and inefficient due to narrow windows of time for effective control (after adults emerge from canes, but before egg-laying begins 7 days later), and the lack of region-specific information to predict emergence and longevity of egg-laying activity. Our project objectives were: 1) to refine determinants of risk to PNW caneberry plantings from RSG through coordinated regional pest surveys, 2) to develop an enhanced integrated pest management (IPM) program with refined information on RSG detection methods, life cycle, and development of a pest management prediction model, and 3) to investigate biocontrol potential of a parasitoid wasp that may mitigate RSG’s viability and play a role in future IPM programs.

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Development of alternate fertilization programs to mitigate nutrient problems found in long-term organic production systems

In long-lived organic blueberry production systems, nutrient imbalances caused by some fertilization and mulching practices can reduce yield and plant health. The ability to balance nutrient levels and thus improve productivity over time was evaluated in a mature planting of ‘Duke’ and ‘Liberty’ that had previously been used to study different mulching practices and various rates and sources of fertilizer. The prior fertilizer treatments were feather meal and fish emulsion, each applied initially at “low” and “high” rates of nitrogen (N), 29 and 57 kg·ha-1 N in 2007–08 and then increased incrementally as the planting matured to 73 and 140 kg·ha-1 N in 2013–2016. Mulch treatments included sawdust (9-cm deep), yard-debris compost (4-cm) + sawdust (5-cm) and weed mat. In winter 2016-17, existing weed mat was removed from plots where it was present, and new weed mat was installed on top of any existing organic mulches – thus changing the mulch treatments to weed mat (over bare soil), weed mat over sawdust, and weed mat over compost + sawdust from 2017–2020.

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